Headphones (or headsets) and ear protectors are often uncomfortable due to the pressures they exert on a user's head and ears. Headphones or ear protectors designed for noisy environments include features that reduce or eliminate environmental noise. The most common type of headset or ear protection consists of a left and right earcup that physically shields the ears from outside noise. Active or electronic noise canceling is also commonly implemented to reduce noise levels further than passive methods alone achieve.
The effectiveness of passive noise reduction or noise shielding is often dependent on how well the earcups are mated to the user's ears and head. A poor seal results in more noise. A common cause of a poor seal between an earcup and a user's head is due to the difficulty of adapting a headset to the different sizes and shapes of heads; especially the non-uniform shape surrounding the ear where the earcups mate to the head.
Headsets and ear protectors are often designed with a one-size-fits-all approach where the headset includes thick cushions which bend and conform to the user's head in order to mate the earcups to the head. The cushions are designed of material that acoustically reflects and/or absorbs sound, minimizing the sound that passes through the cushion to the inside of the earcup. This method carries the drawback that enough clamping pressure must be applied to the earcup so as to force the cushion into compliance with the head, and this necessary pressure often becomes uncomfortable over time. In order to fit a wide variety of heads, sufficient pressure must be applied to the earcups and cushions to conform the cushion to larger or smaller heads of various shapes. Thus the pressure may be more than necessary to achieve the desired noise reduction, or it may be less than needed, so the comfort level and/or the noise level is not optimized.
Another pressure point applied to the head by headphones or ear protectors is across the headband. The headband holds the headset in place so the earcups stay fixed over the ears. The headband, in combination with stirrups on each side of the headband, also provides a mechanical connection between the earcups so that sufficient pressure may be exerted to conform the earcup cushions to the head. The weight of the headphones is the primary force causing the headband to apply pressure to the top of the head. Ideally, a headset would apply the pressure evenly across the top of the head, and distribute the weight over as large an area of the head as possible. Unfortunately, headset manufacturers use a one-size-fits-all approach which applies most of the weight of the headset to a few points on the user's head, rather than distributing it evenly and across a large area.
Headphones and ear protectors typically use earcups shaped like an ear or ellipse, rather than round earcups. The earcups follow the shape of the ear as closely as possible in order to maintain a better noise seal, since variations in head shape become larger as distance from the ear increases. One problem headsets have with an ear-shaped earcup is that it prevents the user from moving the headband to the most comfortable position on their head, since moving the headband also rotates the earcup around the ear. If a user moves the headband to a comfortable position, the earcup may no longer be aligned correctly with the ear. Thus, it is often undesirable for the user to necessarily change the width, length, or shape of the headband when the user adjusts clamping pressure because the shape of the headband is a separate factor affecting comfort. It is desirable for shape and pressure to be adjustable in isolation of each other. Further, it is often desirable to have a single control for adjusting clamping pressure of both earcups, rather than a separate control for each earcup. However, typical headphones often require a separate control for each earcup or cause the adjustment of shape and pressure to not be adjustable in isolation of each other.
Many headphones have a cord, microphone, or other feature on one side of the headphone. The feature may be on the wrong side for maximum comfort and convenience. For example if the user is a pilot, the headset cord may be on the right side of the headset while the headset jacks in his aircraft are on the left, causing the cord to cross his lap. Another example is if the microphone boom is on the left side of the headset, and interferes with an oxygen boom which is also on the left. Some headset manufacturers simply allow the headset to be turned around, placing the cord and microphone on the opposite side; however this causes the right and left audio to be swapped causing right audio in the left ear and vis-versa. For a pilot, this can be a problem since some Traffic Collision Avoidance Systems (TCAS) send verbal traffic warnings to the right earphone if another aircraft is detected on the pilot's right or 3 o'clock position. Thus the stereo spatial direction the pilot hears the warning coming from in his headset is the direction he should look to see the threat.